.TH std::experimental::find_first_set,std::experimental::find_last_set 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::experimental::find_first_set,std::experimental::find_last_set \- std::experimental::find_first_set,std::experimental::find_last_set

.SH Synopsis
   Defined in header <experimental/simd>
   template< class T, class Abi >                    \fB(1)\fP (parallelism TS v2)
   int find_first_set( const simd_mask<T, Abi>& k );
   template< class T, class Abi >                    \fB(2)\fP (parallelism TS v2)
   int find_last_set( const simd_mask<T, Abi>& k );

   1) Returns the lowest index i where k[i] is true.
   2) Returns the greatest index i where k[i] is true.

   The behavior is undefined if any_of(k) is false.

.SH Parameters

   k - the simd_mask to apply the reduction to

.SH Return value

   An int in the range [0, simd_size_v<T, Abi>).

.SH Example


// Run this code

 #include <cstddef>
 #include <experimental/simd>
 #include <iostream>

 namespace stdx = std::experimental;

 template<typename Abi>
 int find(stdx::simd_mask<Abi> const& v)
 {
     if (stdx::any_of(v))
         return find_first_set(v);
     return -1;
 }

 int main()
 {
     stdx::simd_mask<short> a{0};
     a[2] = a[a.size() - 2] = 1;

     for (std::size_t i = 0; i < a.size(); ++i)
         std::cout << a[i] << ' ';
     std::cout << '\\n';

     std::cout << "find_first_set: " << stdx::find_first_set(a) << '\\n';
     std::cout << "find_last_set: " << stdx::find_last_set(a) << '\\n';
     std::cout << "find: " << find(a) << '\\n';
     a[2] = 0;
     std::cout << "find: " << find(a) << '\\n';
     a[a.size() - 2] = 0;
     std::cout << "find: " << find(a) << '\\n';
 }

.SH Possible output:

 0 0 1 0 0 0 1 0
 find_first_set: 2
 find_last_set: 6
 find: 2
 find: 6
 find: -1
